Diversity and Prevalence of Gastrointestinal Helminths of Free-roaming Dogs on Coastal Beaches in Ecuador: Potential for Zoonotic Transmission

Free-roaming dogs are highly exposed to a range of zoonotic parasites, including helminths, which can be transmitted to humans, particularly in rural tropical settings of developing countries. To evidence the diversity and prevalence of gastrointestinal helminths in the stools of free-roaming dogs on the public Pacific coastal beaches of Ecuador, a cross-sectional study was conducted from August 2021 to August 2022. The sampling beaches are located along the tropical Pacific coastal region. Stools were collected from the ground in containers with 10% formalin and processed using the Ritchie method; eggs were identified under a microscope. A total of 573 stools were examined from 20 beaches; the overall prevalence was 157 (27.4%) for one or more helminths. Ten parasites were identified, nine of which are potentially zoonotic. Ancylostoma spp. was the most prevalent (19.4%), followed by Toxocara spp. (7.2%). Trichuris spp., Dipylidium caninum, Diphyllobothrium spp., Capillaria spp., Dicrocoelium spp., Heterobilharzia americana, Hymenolepis spp. and Spirocerca spp. were also observed. Five of them are reported for the first-time infecting dogs in Ecuador. Hence, we evidenced that Ecuadorian beaches are highly contaminated with the dogs' zoonotic gastrointestinal helminths, posing a great risk to public health. Differences in the presence and prevalence were found in samples of tropical humid and dry climate zones. Therefore, based on our findings, we encourage the implementation of broad antiparasitic treatment and prevention strategies to reduce the zoonotic risk.